Lead manufacture



Aug 8, 1939- w. H. wooDFoRD 2,168,381

LEAD MANUFACTURE Filed June 8, 1932 FIG.

INVEN TOR.

WATSON H, WooDFoRn ATTORNEY Patentedl Aug. 8, 193% LE' MANUFACE Watson E. Woodford, Bridgeport, Conn., assignor to Remington Arms Company, inc., a corporation of Delaware Application .rune s, 1932, serai N. 616,024

23 Claims.

This invention relates to the production of a particular form of lead, and to certain uses of lead in this form; one of which uses is .for

projectiles, particularly small caliber projectiles designed for use in shooting galleries.

In one aspect the invention contemplates a projectile or bullet adapted to be completely disintegrated upon impact with a hard impervious surface, such as the steel plates universally used as target backings in shooting galleries.

The lead bullets hitherto used in cartridges designed for rified rearms, particularly small caliber rifles, have been made by the forming of slugs of solid lead, either by individual molding or by shearing from a wire, and the swaging of such slugs to the desired shape. When such bullets are fired against a steel plate the forward part of the bullet which, upon impact with the target, is traveling with a velocity of the generalorder of 1,000 feet per second, appears to be quite completely disintegrated. The energy consumed in the disintegration of the forward portion greatly reduces the velocity of the rearward portion, which breaks into comparatively large fragments that may be projected" in various directions generally transverse to the surface of the impacted plate with very substantial velocities. Such fragments may again be deected from the walls or ceiling ofthe gallery and, being of irregular shape,Y their course of flight is very erratic. .It has occasionally happened that such fragments were so deflected as to return substantially to the position from which the cartridge was red, and accidental injury to the shooter and other persons located at the shooting position due to such iiying fragments is not unknown.

The present invention is a development of research intended to produce a bullet incapable of projecting any fragments of substantial size from the surface of a hard target. The invention, however, goes substantially beyond the manufacture of bullets, and contemplates a particular and hitherto unknown form of lead, and methods and articles generally comprising the use of lead in this form.

In the drawing:

Fig. 1 is a diagrammatic representation in sec-g tional elevationl of an extruding die designed to produce a brous lead wire from a spongy iibrous lead produced in the manner hereinafter set forth.

Fig. 2 is a sectional elevation of a nozzle for 55 a die of the'type represented in Fig.`1, which nozzle has a distinctly different angle of taper from the nozzle illustrated in Fig. 1.

Fig. 3 is an enlarged plan view of a section of lead wire produced according to the methods of the present invention, and the fracture of such wire under tension.

Fig. 4 is an enlarged plan view of a cartridge ,provided with a bullet made in accordance with the present invention, a portion of said bullet having been removed by the application of a tension stress, exposing the fibrous interior.

The invention contemplates the division of solid metallic lead into a spongy mass of separated iibres. It has been found that such a separation of lead may be secured by dropping lead in a thin stream into certain fluid solutions. Numerous acid and salt solutions are effective for this purpose, but it is preferred to use a solution having the property of coating the lead fibres in such a way that they do not coalesce into a homogeneous mass under thev treatment to which they are subsequently subjected, as hereinafter described. Coatings of two quite diierent natures have been successfully used. The rst is a coating of another metal, such as copper or cadmium. which is secured by using a solution of copper sulphate, copper cyanide, or cadmium cyanide, galvanic action being effective to produce a very thin coating of copper or cadmium on the individual bres. Similar coatings of any desired metal can readily be secured by making the solution into which the molten lead is dropped an ordinary electro-plating bath. The second type of coating comprises a salt, such as lead carbonate, lead borate, lead chloride, lead sulphate, lead sulphide, These coatings respectively are secured by the use of solutions of sodium carbonate, boric acid, dilute hydrochloric acid or ferrie chloride, dilute sulphuric acid, and water into which hydrogen sulphide is constantly passed.

One method including the forming of a salt coating is as follows:

A stream of molten lead about 1A ln diameter is dropped a distance of about 2 into a 4% aqueous solution of anhydrous sodium carbonate, this concentration corresponding to about 10.8% of crystalline sodium carbonate. The concentration of the solution, however, may be varied within wide limits, say 8% to 40% of crystalline sodium carbonate. When dropped into such a solution, or a. suitable solution of one of the other substances heretofore mentioned, the lead gathers as a porous, spongy, fibrous mass which is easily disintegrated and is found to consist chiefly of comparatively fine fibres having a dark dull exterior surface which probably contains a substantial amount of lead. carbonate, while the interior of each bre is bright metallic lead. While the reason for this result is not fully understood, it is thought probable that the effect of the impact of hot molten lead with the liquid salt solution is analogous to the wellknown result of dropping water onto a metal plate. If the plate is heated above a certain critical temperature, its surface is not wet, the water is broken up into small spherical or spheroidal drops in which it is retained by'its own surface tension. The disintegration of the heated lead into firm fibres may be caused in a similar manner, and the formation of a coating on the surface of such fibres may assist in preventing their coalescing into a solid mass.

For the manufacture of a wire suitable for the production of lead bullets and for similar uses such fibrous spon'gy lead may be packed in a mold or extruding die, one form of which is diagrammatically illustrated in Fig. 1. Numeral I0 indicates the body of the die, which is preferably of circular cross section and is provided with a nozzle II having an aperture I2 of substantially the diameter of the desired Wire. In the upper portion of the cylindrical die I0 is a plunger I3 adapted for actuation by a suitable source of power, such as a hydraulic press. The charnber of the die I0 is charged with spongy fibrous lead I4 and upon the application of pressure through the plunger I3 a Wire I5 of the form illustrated in Fig. 3 is extruded through the nozzle aperture I2. Such wire is found to comprise a continuous exterior sheath I6 of substantially salt free metal having a thickness of the general order of .001. The exterior fibres appear to becoalesced into this continuous sheath by friction with the nozzle. Within the sheath the wire substantially consists of a bundle of longitudinally disposed fibres, each probably more or less coated, as heretofore stated, with lead carbonate. 'Ihe fibres adjacent the sheath may coalesce to a certain extent, but never into masses of substantial size. The extremely fibrous character of the wire is very apparent upon fracturing the wire either by flexure or tension. The general appearance offa tension fracture has been illustrated in Fig. 3. The diameter of the individual fibres varies substantially but does not ordinarily exceed .0030". The nozzle II in Fig. 1 may have a taper angle of 90. It appears that the compactness of the fibres in the extruded wire may be somewhat varied by altering the angle of taper of the nozzle. Fig. 2 shows a nozzle IIa having a taper angle of 120. Variation in the compacting of the fibres is likewise effected by the quantity of lubricant upon the die. A very loosely compacted wire is secured by the use of an excess of lubricant, the lubricant probably entering the body of the wire and to a certain extent coating the individualiib'res. A wire of a diameter of .2" is fractured under a tension stress of between and 50 pounds, the fracture invariably occurring at the clamping device by which the wire ls supported, probably on account of the weakening of the homogeneous, smooth and continuous exterior lead coating.

Lead or lead wire in this form is suitable lfor any purpose where low tensile strength and/or ready disintegration are desirable. Fig. 4 illustrates a rim-fire cartridge I'I provided with a bullet I8 formed by the usual swaging of' a. slug cut 4from a wire of the character above-described.

The bullet has been subjected to a tension stress with the result that a part of the exterior continuous coating has been removed, showing clearly the fibrous structure of the interior. Numerous tests made by firing such bullets against steel plates indicate that they are substantially completely disintegrated. Not more than 6% of the bullet material remains on a live-mesh screen and not more than .5% in addition remains upon a ten-mesh screen, while approximately '15%,4

passes a twenty-mesh screen. When ordinary solid lead bullets are similarly tested about 22% remains on a five-mesh screen and not less than 44% on a ten-mesh screen. It is thus seen that with the improved bullets of the present invention the annoyance and danger incident to the projection of bullet fragments from a hard target or target backing are entirely eliminated.

The invention, however, contemplates not only the production of bullets, but the method of securing fibrous lead and manufactures generally comprising such lead, and the appended claims are to be broadly construed.

What is claimed is:

1. A projectile consisting substantially of extended, longitudinally disposed lead fibres.

2. A projectile consisting substantially of extended, longitudinally disposed lead iibres and having a continuous surface.

3. A projectile consisting substantially of extended, longitudinally disposed lead fibres encased in a continuous lead sheath.

4. A projectile consisting substantially of lead particles each coated with a lead salt.

mass of lead particles separated by coatings on said particles.

7. A projectile v consisting substantially of a continuous lead sheath enclosing a mass of compacted individual particles, said individual particles being coated with lead carbonate.

8. A firearms projectile consisting of fibres of lead suflciently compacted to withstand without disruption the stresses of being projected through and from a firearms barrel and to be disrupted into small fragments on impact with a hard target.

9. A firearms projectile consisting of metallic fibres encased in a continuous sheath and sufficiently compacted to withstand without disruption the stresses of being projected through and from a firearms barrel and to be disrupted into small fragments on impact with a hard target.

10. A firearms projectile comprising a mass 0f metallic libres compacted under sufficient pressure to cause the exterior fibres to coalesce and vform a continuous sheath or jacket.

11. A firearms projectile comprising acore of compacted dispersed metal and a covering for said core consisting of the same dispersed metal' .which has been coalesced by compression into a continuous sheath.

12. A firearms projectile comprising a mass of lmetallic fibres and ,a continuous exterior sheath formed by coalescing said libres under pressure.

13. The method of making projectiles which comprises the compacting of dispersed metal to form the c'ore of the projectile, and the coalescing of 'such dispersedmetal to form a continuous sheath surrounding said core.

14. The method of making projectiles which comprises the compacting of dispersed metal t0 form a fibrous core and the coalescing of such dispersed metal to form a continuous sheath surrounding said core, said compacting and c0aleScing being performed by extruding said dispersed surrounding said core.

16. The method of making projectiles which comprises dispersing a metal, compacting such dispersed metal to form a projectile core, and simultaneously coalescing the surface portion 0f such dispersed metal to form a continuous sheath surrounding` said core, said compacting and coalescing being done in an extruding die.

17. The method of making projectiles which comprises dispersing projectile metal by dropping a continuous stream of said metal while fluid into a uid medium, and collecting and compacting said dispersed metal into projectiles.

18. The method of making projectiles which comprises dispersing projectile metal by dropping said metal while uid into a solution of a suitable salt, and collecting and compacting said dispersed 0 metal into projectiles.

comprises dispersing projectile metal by dropping said metal while fluid into a solution of a material selected from a group comprising sodium carbonate, boric acid, dilute hydrochloric acid or ferrie chloride, dilute sulphuric acid, and hydrogen sulphide water, and collecting and compacting said dispersed metalinto projectiles.-

20. The method of making projectiles which comprises dispersing projectile metal by dropping said metal while fluid into a carbonate solution, and collecting and compacting said dispersed metal into projectiles.

21. The method of making projectiles which comprises dispersing projectile metal by dropping.

said metal while fluid into a solution of sodium carbonate, and collecting and compacting saidv dispersed metal into projectiles.

22. The method of making projectiles which A comprises dispersing projectile metal by dropping said metal while iiuid into a solution having a concentration from 8% to 40% of crystalline sodium carbonate. and collecting and compacting said dispersed metal into projectiles.

23. The method of making projectiles which comprises dispersing projectile metal by dropping said metal while fluid into a solution having a concentration of approximately 10% of crystalline sodium carbonate, and collecting and compacting said dispersed metal into projectiles.

WATSON H. WOODFORD. 

